Generally, Nucleic acid automation analyzers and blood analyzers are equipped with an incubator capable of maintaining samples, such as blood or DNA taken from specimens, at any desired processing temperature as it is necessary for these analyzers to perform various kinds of processing on the samples at optimum processing temperatures before analyzing the samples.
A conventional incubator is constructed such that a storage block which can accommodate reaction vessels loaded with samples is fitted with a thermo-module, by which the storage block is heated or cooled in accordance with specified processing temperatures. In this type of construction, in which the whole of one storage block is heated and cooled, a long period of time is required for controlling it from one processing temperature to another, causing a significantly long waiting time, if there is a large temperature difference between successive processing steps. A proposal made in a recent year (Japanese Unexamined Patent Publication No. HEI 6-277036) discloses a construction as shown in FIG. 9, in which a cooling block 53 cooled by a cooling fan 51 and a radiator plate 52 and a heating block 55 heated by a heater 54 are individually preset to their cooling and processing temperatures, respectively, and reaction cuvettes 56 are moved back and forth between the two blocks 55, 53 to thereby reduce the waiting time required for temperature control.
There exists a problem in such conventional construction simply incorporating the cooling block 53 and the heating block 55, however, that it is difficult to control the temperature following any desired processing temperature settings at a high speed. This is because the temperature in the heating block 55 is controlled by a heating process performed by the heater 54 and a heat dissipation process.
More specifically, it would be possible to achieve an increased rate of temperature rise in the heating block 55 by adopting measures such as increasing a capacity of the heater 54, reducing a capacity of the reaction cuvettes 56, or a greater heat insulating ability, for example. It is however difficult in actuality to take measures such as reducing the capacity of the reaction cuvettes 56 or the increasing the capacity of the heater 54, since an analyzer to be equipped with the incubator is restricted in its specifications. On the other hand, the greater heat insulating ability is extremely important in ensuring the stability of temperature required for the incubator. Therefore, the increase in the rate of temperature rise in the heating block 55 is usually realized by taking measures which are mainly focused on the heat insulating ability and yet permit increased stability of temperature.
If, however, the heating block 55 is so constructed as to achieve great ability of heat insulating, the rate of heat dissipation during a process of temperature drop, which occurs after stopping the heating process by the heater 54, decreases and, as a consequence, the process of temperature drop slows down. For reasons stated above, it has been necessary to sacrifice at least one of the temperature rise efficiency and the temperature drop efficiency in the conventional incubator and, therefore, it has been difficult to control the temperature following any processing temperature settings at a high speed.
Accordingly, it is an object of the invention to provide an incubator which permits high-speed temperature control, swiftly following arbitrarily any processing temperature settings, by increasing both the rate of temperature rise and the rate of temperature drop as well as an analyzer equipped with such incubator.